Apparatus and process for bulking yarn



Jan. 7, 1964 H. SCHERZBERG ETAL 3,116,532

APPARATUS AND PROCESS FOR BULKING YARN Filed June 27, 1961 INVENTORS. HERBERT SCHERZBERG, ERNST MOSS/G.

ATTORNEYJ United States Patent APPARATUS AND PROCESS FOR BULKING YARN Herbert Scherzberg and Ernst Mossig, Dormagen, Germany, assignors to Farbenfabriken Bayer Aktiengesellschaft, Leverkusen, Germany, a corporation of German y Filed June 27, 1961, Ser. No. 120,031

3 Claims. (Cl. 281) The invention relates to an apparatus for the production of loops in the capillary filaments of a yarn consisting of endless synthetic threads, which apparatus consists of a nozzle with a lateral air-inlet union and a central yarnguiding tube projecting into the nozzle duct. A threaddeflecting member is arranged outside the nozzle. The loop formation in the capillaries of the yarn takes place inside the nozzle at the point where the yarn leaves the central guiding tube by whirling of the yarn in the air stream entering the nozzle from the side. The twisted filament is swung backwards and forwards and is twisted alternately to the left and right, so that the loop formation of the capillaries, depending on whether the yarn has a S- or Z-twist, is impaired or undesirably strengthened and thus becomes irregular.

These disadvantages are obviated according to the invention by providing the yarn-guiding tube with a bevelled surface at its outlet end. The result achieved by this is that the thread is set in its position at the upper edge of the yarn-guiding tube on being withdrawn from the latter. Consequently, a twisting of the thread at the end of the yarn-guiding tube is avoided, so that a regulated and equalised loop formation is produced in the capillary filaments by the eddying air stream. The filament is withdrawn to one side or the other, depending on whether the yarn has a S- or Z-twist. In order to obtain an eddying zone which is of satisfactory aerodynamic form, the elliptical area of the bevelled end of the yarn-guiding tube should be practically equal to the circular area of the nozzleoutlet opening and the nozzle duct should be at least twice as long as the projection of the major axis of the ellipse on the longitudinal axis of the yarn-guiding tube.

One embodiment of the invention is shown diagrammatically and by way of example in the drawing. FIG. 1 shows a longitudinal section through the nozzle, while FIG. 2 is a longitudinal section through the same nozzle, but rotated through 90 about the longitudinal axis.

In the figures, the reference 1 indicates the nozzle element, 2 the internal space of the nozzle, 3 the yarnguiding tube which is arranged centrally in the nozzle and projects into the nozzle duct 4, 5 the lateral inlet union for the air stream, 6 the nozzle opening, 7 the elliptical area of the bevelled end of the yarn-guiding tube 3, 8 the thread and 9 a thread-guiding member externally of the nozzle.

The air stream entering the internal space 2 of the nozzle 1 through the lateral inlet union 5 draws the twisted thread 8 to be treated in upward direction through the guide tube 3. The thread 8 is withdrawn from the nozzle duct 4 via the roller 9 in such a manner that the thread abuts against the upper outlet edge 10 of the bevelled end of the guide tube 3 and is set in its position at the upper edge of the yarn-guiding tube during travelling so that the thread cannot oscillate in the nozzle opening 7 to and fro transversely of its travelling direction. When leaving the edge 10 of the bevelled guide tube 3 the thread 8 is partially twisted under the influence of the air eddying stream in the nozzle duct 4. The externally disposed capillaries or elementary filaments of the twisted thread are thereby pulled out in the form of loops from the twisted parts of the twisted thread.

After the passage of the thread through the eddy zone, i.e. when the thread issues from the nozzle duct 4 into the open, the parts of the thread which are twisted under the influence of the eddy stream in opposite direction to the original twist of the yarn, jump back into the original position while looking the elementary filaments pulled out in the eddy air stream with loop formation and thus producing loops on the thread. By setting the travelling thread in its position at the upper edge 10 of the bevelled end of the guide tube 3 uniform twisting of the thread over its entire circumference is guaranteed so that uniform loop formation over the entire circumference is produced.

Several guide tubes 3 may be arranged in juxtaposition.

We claim:

1. Apparatus for the production of loops in the capillary filaments of a yarn consisting of endless synthetic threads, comprising a nozzle with a lateral air inlet, said nozzle terminating in a nozzle duct having a circular flow cross-section, and a central yarn-guiding tube having a circular flow cross-section disposed in said nozzle and terminating in an outlet end projecting into the nozzle duct to form an annular air passage portion therebetween, the yarn-guiding tube being bevelled at said outlet end and having an elliptical rim which is defined in a plane intersecting the longitudinal axis of said tube at an acute angle therewith, the elliptical rim cross-sectional area of the outlet end of the yarn-guiding tube being practically equal to the circular cross-sectional area of the nozzle duct, and the length of the nozzle duct being at least twice that of the projection of the major axis of the ellipse defined by said rim on the longitudinal axis of the yarn-guiding tube.

2. In an apparatus for the production of loops in the capillary filaments of a continuous yarn composed of endless synthetic threads, including means defining a nozzle chamber having a forward end and a rearward end, said forward end terminating in a nozzle duct provided with a circular flow-cross section, a lateral air inlet communicating with said nozzle chamber at said rearward end, and a circular flow cross-section yarn-guiding tube disposed in said nozzle chamber and terminating in an outlet end, said outlet end projecting into said duct to form an annular air passage therebetween, the improvement which comprises providing said tube with a bevelled outlet end having a guide rim with an elliptical configuration situated in a plane intersecting the longitudinal axis of said tube at an acute angle therewith, the convex side of one of the narrow arcs of the elliptical rim extending in the direction of said forward end to define thereat a laterally restricted guide path of travel for the yarn.

3. In the method for the production of loops in the capillary filaments of a continuous yarn composed of endless synthetic threads by conducting the yarn through a tube having a circular flow cross-section and terminating in an outlet end, said tube being concentrically positioned within a nozzle having a circular flow cross-section, said nozzle having a forward end terminating in a nozzle duct surrounding said outlet end, and thence conducting said thread from the end of the tube through said nozzle duct in an air stream passing through said nozzle and around 1% 4 said tube and outlet end and out of said duct to cause the and thence through said duct, whereby the passing air formation of loops in the yarn filaments, the improvement stream will cause the loop formation to be effected without which comprises using a tube for said yarn provided with oscillating said yarn along the rim of said outlet end. a bevelled outlet end having a guide rim with an elliptical configuration situated in a plane intersecting the longi- 5 References Cit d i h filg f hi patgnt tudinal axis of the tube at an acute angle therewith, the

convex side of one of the narrow arcs of the elliptical rim UNITED STATES PATENTS extending in the direction of the forward end to define 2,884,756 H ad May 5, 1959 thereat a laterally restricted guide path of travel for the 2 P0 1 May 2, 1961 yarn, and passing said yarn through said, tube ,and against 10 FOREIGN PATENTS said bevelled outlet end withln said guide path of travel, 912,655 Germany Feb. 7 1955 

1. APPARATUS FOR THE PRODUCTION OF LOOPS IN THE CAPILLARY FILAMENTS OF A YARN CONSISTING OF ENDLESS SYNTHETIC THREADS, COMPRISING A NOZZLE WITH A LATERAL AIR INLET, SAID NOZZLE TERMINATING IN A NOZZLE DUCT HAVING A CIRCULAR FLOW CROSS-SECTION, AND A CENTRAL YARN-GUIDING TUBE HAVING A CIRCULAR FLOW CROSS-SECTION DISPOSED IN SAID NOZZLE AND TERMINATING IN AN OUTLET END PROJECTING INTO THE NOZZLE DUCT TO FORM AN ANNULAR AIR PASSAGE PORTION THEREBETWEEN, THE YARN-GUIDING TUBE BEING BEVELLED AT SAID OUTLET END AND HAVING AN ELLIPTICAL RIM WHICH IS DIFINED IN A PLANE INTERSECTING THE LONGITUDINAL AXIS OF SAID TUBE AT AN ACUTE ANGLE THEREWITH, THE ELLIPTICAL RIM CROSS-SECTIONAL AREA OF THE OUTLET END OF THE YARN-GUIDING TUBE BEING PRACTICALLY EQUAL TO THE CIRCULAR CROSS-SECTIONAL AREA OF THE NOZZLE DUCT, AND THE LENGTH OF THE NOZZLE DUCT BEING AT LEAST TWICE THAT OF THE PROJECTION OF THE MAJOR AXIS OF THE ELLIPSE DEFINED BY SAID RIM ON THE LONGITUDINAL AXIS OF THE YARN-GUIDING TUBE. 